Through the drilling of thicker conglomerate in largeborehole, the new requirement for the manufacture of drilling tools has been put forward.
通过该井大井眼巨厚砾石层的钻进,对钻井工具的制造也提出了新的要求。
2
The large diameter direct drainage borehole is used to strengthening mine drainage capacity, to ensure coalmine safety production.
大孔径直排孔的作用是加强矿井排水能力,保证煤矿安全生产。
3
Taking two of projects as examples, the paper discussed the technology of large diameter borehole blasting applied in the excavation of footing groove in city.